A Novel Air Backwashing Method for Reversing Wetting in Membrane Distillation

This paper describes a new method to reverse wetting of the hydrophobic membrane in membrane distillation. Pressurized air is pushed through the wetted membrane from the distillate side, thus forcing out wetted feed water, instead of merely allowing it to evaporate. To test its effectiveness, the liquid entry pressure (LEP) of the membranes was tested before and after the pressurized-air process. The results reveal that the air backwashing method was very effective, restoring LEP to nearly 85% of the original value, without requiring the long delay times associated with dryout.